Electric hammer



Aug.-31;' 1'9 18. c. BROWN ETAL ELECTRIC HAMMER 3 Sheets-Sheet l Filed Oct. 17, 1946 Fig. 8

Aug. 31, 1948. I c. BROWN ETAL 0 ELECTRIC HAMMER Filed Oct. 17, 1946 Q 3 Sheets-Sheet 2 BY H.

g 31, 1948- c. BROWN EI'AL 2,448,210

ELECTRIC HAMMER Filed Oct. 17, 1946 3 Sheets-Sheet 3 Fig. 3

I4 Fig. 5

46 44 v .By wl 7e Patented Aug. 31, 1948 ELECTRIC Harman Curtis Brown, Martinton, aiid William iarke,

Chicago, Ill. Application October 17, 1946, Serial No. 103,790

4 Claims. (01.153432) This invention relates to power hammers and I more particularly to an electrically operated hfammer for use in automobile body and fender work, riveting and the like.

One of the objectsof this inventi'onis the provision of a portable electrically operated hammer which is light in weight, which is easily manipulated and which requires comparatively little skill to operate.

Another object of this invention is the provision of an electrically operated hammer in which the frequency of the blows delivered by the hammer is comparatively high.

A further object of this invention is the provision of an electrically operated hammer in which the force of the blow delivered by the hammer may be adjusted to conform same to various types of work.

A still iurthe'r'object of this invention is the provision of an electrically operated hammer,

which, can be swung around 'on its frame so that work may be done in restricted places.

More particularly,it is intended to provide a generally (w-shaped frame carrying an opposed hammer and anvil at the upper and lower'terminal, re-

spectively, of the c, the frame being adjustably deformable for opening or closing the 0, whereby the frame may be opened up for insertion of the hammer or anvil in close or cramped quarters. This, coupled with the arrangement for swinging the hammer with respect to'the frame, is intended to provide for almost universal utility in the ap- Fig. 1 is an elevational view of my hammer and mounting as it would appear in use.

Fig. 2 is a view partially in cross section and partially in elevation of the hammer showing the hammering mechanism at the bottom of an operating stroke. I I

Fig. 3 is a similar view showing the hammering mechanism at the top .ofan operating stroke.

Fig. 4 is a vertical section taken on line. 4-4 or Fig. 3.

Fig. 5 is a horizontal section taken on lined-5 of Fig. 3. I

Fig. 6 is a vertical section taken on line '6--6 of Fig. 2.

I Fig. 'I is a horizontal section taken on line 1--'I 'orriaz.

8 is a vertical section taken 'on line 8-8 of Fig. l.

Fig. '9, is an. elevational view showing the hammer unit used independently of the frame.

In the embodiment Of, my inyentibnflas illusti'ated-inthe drawings, T indicates a housing which is adapted to contain the hammer and 013- eratm'g mechanismtherefore, presently to be 61 scr'ibed; Said housingissubstantially T-shaped and comprises a vertical tubular member l2 'whijch forms" the head of the T; and a horizontal member l4. The member l l'fwl'iich forms the staff or the T terminates in anenlarged portion l which servesaspar't of the housing for the motor 15. integrally formed with the housing leis a handle 11 which'isadapted to house'an electric switch l8.

Mounted on'the enlarged portion 15 isan electric motor I15 which serves as the operating means r he hammer. A motor shaft?!) provided with a squared end portion '22 is journaled in a roller bearing 24 and extends into the tubular member I4. .Mounted in bearings .26 and Z'ifin the. tubular member I 4 is a'shaft 28 which is provided with a squared "end portion 29. Acoupling 39 re-- ceivesthe squared end portions 22 and 29 of the shafts 2'0 and '28 respectively and forms a driving connection between the motor shaft and the shaft 28. A packing nut 3 is screwed into a threaded portion of the 'tubular member I4 and serves to retain the packing 3'3 aroundthe shaft 28. A set screw 32 for securing the packing nut 34 in'position and a grease fitting 35 are provided the member I4. Mounted for rotation therewith on the shaft 28, intermediate of the bearings '26 and 21 is a worm 36 which is adapt'edto engage the pinion 38. Pinion 38zis mounted on a transverse shaft 40 which is journaled in roller bearings 42, 42. As shown in Figure 4, the bearings 42 are mounted in the web members '44 which screw into the opposite sides 'of the housing 10.

Mounted on the opposite sides of pinion 38 *on the shaft 40 for-rotation therewith is a pair of cams 46. 46 in alignment with each other. "The cams 46 have oppositely positioned high pertions, preferably l80 from each other,-which, whenrota-ted impart reciprocating movement .to the hammer stem 48 in a manner presently to be described. v I

The hammer stem 48 is mounted for, reciprocat ing movement in the vertical member 12 of the housing In which has a square shaped bore 49. The hammer stem comprises an upper portion 50 which is square in cross section and a lower cylindrical portion 52 formed integrally therewith. A shoulder 53 is formed at the junction of the per:- tions 5.0 nd 52, against which .the camsMiem gage during operation of the hammer. The upper portion 58' is provided with a circular recess .54 which is adapted to serve as aseat for-the actuating spring 55. A longitudinal recess 56 in the square portion 58 serves to provide clearance for the worm gear 38. x

A spring 58'is'mounted in themember i2 and abuts, at its upper end, against a washer 59 which in turn rests against a. shoulder 60 pro-- j vided in the member I 2, and at its lower end against an externally threaded bushing desig-- nated 62 in Fig. 3 in threaded engagement with an internally threaded portion in the lower end.

of the member II. The bushing 62 comprises two independent sections 82a and 62b, as shown in Fig. 2 having their opposed faces machined-to end of the portion 65 ,of the hammer stem 48.

A knurled nut 69 provided with internal and external threads cooperates with the internally threaded portion of the member l2 and with the externally threaded spring adjusting sleeve 10. It will be seen that by means of the knurled knob 18' secured to the adjusting sleeve 10, the compression of the actuating spring 55 which abuts the under side of same can be easily adjusted. By regulating the compression of this spring the force of a blow required for a particular kind of work can be easily controlled by the operator.

Supporting the entire hammer unit is a horizontal tubular arm 13 having at one end a. sleeve 14 positioned at right angles, and which serves as a continuation of the member l2. A bushing .15 is provided interiorly of sleeve 14 and is retained in position by a locking nut 16 which engages external threads at the upper portion of the sleeve. The lower portion of sleeve "is provided with internal threads which receive an externally threaded sleeve member 11 which serves as a guide for the hammer head 65. By threaded adjustment of sleeve member 1'! upwardly and downwardly is sleeve 14, the gap between sleeve 11 and anvil '95 can be regulated, thus to regulate the effective bite of the hammer. It isthus apparent that when the hammer assembly is not otherwise held, that it may be freely swung in bushing about the vertical axis of the hammer.

by reference to the drawings that when the pin BI is withdrawn from the socket 85 the motor housing can be swung around the vertical axis ofthe hammer stem 48 using the bushing 15 as a bearing surface.- This arrangement is particularly desirable when work is being done in restricted places and where itis inconvenient to use the device in the rigid position shown in the drawings. The movement of the motorv housing in this manner does not in any way eifect the eye bolt 80.

4 positioning or operation of the hammering mechanism.

In Fig. 1 is. shown a preferred formof frame for supporting the hammer and anvil, this frame being capable of being positioned in a vice or being used in a portable manner. The frame is 7 generally C-shaped and comprises a horizontal l8, and which is pivotally mounted as at 'H' on a substantially U-shaped lower frame member 12, the free end of which forms the lower jaw of the C. The lower frame member is provided with lugs 18 which are adapted to receive a pin 19 for pivotally supporting an eye bolt 80. The horizontal arm 13 is provided with a boss 86 which is angularly drilled to accommodate the A wing nut 81 on the eye bolt 88 serves to secure the frame members 12 and 13 in rigid relationship for operation.

.As shown in Fig. 2 the free end of the lower frame member 12 is provided with a socket 88 and flange 89 for supporting an anvil member 9|. While only one form of anvil has been illustrated it will ;be understood that anvil members of different shapes and curvatures for shaping as well as for riveting may be used as required.

Because of the positioning of eye bolt near the pivot pointH of the two frame members H and 72 it will be seen that a very small longitudinal movement of the wing nut 8'! on the eye bolt 88 will permit a comparatively wide separation of the frame members 12 and 73 at their free ends. The insertion of work between the hammer and anvil, particularly that having a high degree of curvature is very easily accomplished with a minimum of adjustment.

The operation of the device is particularly simple; requiring very little experience on the part of the operator. The wing nut 81 is unscrewed to separate the frame members 12 and 13 to permit the insertion of the work '85 therebetween and is thereafter tightened. When the motor [6 is started by means of the switch I 8 the worm is caused to rotate the worm gear 38 and cams 46 in a counter clockwise direction. The cams 46 engage the shoulder 53 of the hammer stem 48 and lift it upwardly against the compression of the spring 55. When the limit of upward travel is reached the cam 46 is freed from the shoulder 53 of the hammer stem 48 and the actuating spring 55 expands to force the hammer stem 48 downwardly, imparting a blow through the hammer head 66. The hammer stem 48 in its downward travel tends to compress, to a very small degree, the spring 58 which serves to absorb some of the shock of the blow and thereby reduces vibration. As the cams 46 rotate the hammer stem 48 is lifted up and the same cycle of operations just described follows through. The force of the blow is easily adjusted by turning the spring adjusting sleeve HI to increase or decrease the compression of spring 55.

pendently thereof. When used in such a manner the unit 16 is unscrewed and the hammer unit slipped out of its support in the member 14. A sleeve :96 substantially of the same construction as the member 14 is positioned over the lower portion of the hammer unit and secured by the nut 16.

It is to be understood that the form of my invention, herewith shown and described, is to be taken as a preferred example of the same, and that various changes in the shape, size and arrangement of parts may be resorted to, without departing from the spirit of my invention, or the scope of the appended claims.

We claim:

1. A portable electric hammer comprising, in combination, a generally C-shaped frame including upper and lower jaw elements, an anvil on the free end of the lower jaw element, a hammer, a hammer motor, a driving connection between said hammer and hammer motor, and a generally T-shaped casing therefor, and including head and staff portions, the hammer having a working stroke across the gap of the C-shaped frame towards the anvil and being enclosed by the head portion, the motor and at least a portion of the driving connection being enclosed in said staff portion, means pivotally mounting said head portion on the free end of said upper jaw element for rotation about its longitudinal axis, the stafi portion normally extending along the upper side of said upper jaw element a handle extending between said head and stafi portions, and means releasably connecting the free end of said staff portion to said upper jaw element.

2. The combination claimed in claim 1, the last-named means comprising a lug extending upwardly from said upper jaw element, socket means on said staff portion, and a detent carried by said lug and releasably engageable in said socket means.

3. The combination claimed in claim 1, the means pivotally mounting said head portion on the free end of said upper jaw portion comprising, a sleeve aflixed on the end of said upper jaw portion, the axis of said sleeve being directed towards said anvil, a bushing in said sleeve, a bearing on said head portion fitting in said bushing, and removable means for holding said bearing in said bushing, whereby said casing and the hammer, motor, and driving connection may be removed as a unit from said frame.

4. The combination claimed in claim 3, and a tubular hammer guide threadedly engaged-on that end of said sleeve which lies nearest said anvil whereby, upon threaded adjustment of said hammer guide, to alter the distance between the same and said anvil.

CURTIS BROWN. WILLIAM F. PARKE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number I Name Date 2,146,358 Seiden et al. Feb. 7, 1939 2,306,600 George Dec 29, 1942 2,365,824 Keesler Dec. 26, 1944 

